CPACK: Improve deb package filenames

[pnx]

This PR fixes the format for deb package filenames to follow the standard debian convention (described here in detail): <PackageName>_<VersionNumber>_<DebianArchitecture>.deb

What is being changed in the original package name is:

• First hyphen is changed to underscore. (right after the package name)
• Last hyphen before the architecture is changed to underscore.
• Use dpkg --print-architecture to get the correct value (e.g. amd64 instead of x86_64 provided by cmake's ${CMAKE_SYSTEM_PROCESSOR})